package net.sxnic.normal.util.verify;

import java.awt.*;
import java.awt.image.*;
import java.util.Random;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.servlet.*;
import javax.servlet.http.*;

@SuppressWarnings("restriction")
public class ValidateNumCode extends HttpServlet {
	
	/**
	 * 数字验证码
	 */
	private static final long serialVersionUID = 1L;

	// 处理post
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 设置页面不缓存
		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);
		
		//获取session
		HttpSession session = request.getSession();

		// 在内存中创建图象
		int width = 70, height = 25;
		BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);

		// 获取图形上下文 
		Graphics g = image.getGraphics();

		// 生成随机类
		Random random = new Random();

		// 设定背景色
		g.setColor(getRandColor(200, 250));
		g.fillRect(0, 0, width, height);

		// 设定字体
		g.setFont(new Font("Times New Roman", Font.PLAIN, 25));

		// 画边框
		g.setColor(new Color(255, 255, 255));
		g.drawRect(0, 0, width - 1, height - 1);

		// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
		g.setColor(getRandColor(160, 200));
		for (int i = 0; i < 155; i++) {
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int xl = random.nextInt(12);
			int yl = random.nextInt(12);
			g.drawLine(x, y, x + xl, y + yl);
		}

		// 取随机产生的认证码(4位数字)
		String sRand = "";
		for (int i = 0; i < 4; i++) {
			String rand = String.valueOf(random.nextInt(10));
			sRand += rand;
			// 将认证码显示到图象中
			g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
			// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
			g.drawString(rand, 13 * i + 10, 21);
		}

		// 将认证码存入SESSION
		session.setAttribute("rand",sRand);

		//response.addCookie(new Cookie("codes", EncodeUtils.cookieEscape(sRand)));

		g.dispose();

		// 输出图象到页面
		ImageIO.write(image, "JPEG", response.getOutputStream());

	}

	static Color getRandColor(int fc, int bc) { // 给定范围获得随机颜色
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}

	public void init(ServletConfig arg0) throws ServletException {
		super.init(arg0);
	}

}